/*
 * Copyright 2011 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package net.peterkuterna.android.apps.devoxxsched.io;

import java.io.IOException;
import java.util.ArrayList;

import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;

import android.content.ContentProvider;
import android.content.ContentProviderOperation;
import android.content.ContentResolver;
import android.content.OperationApplicationException;
import android.os.RemoteException;

/**
 * Abstract class that handles reading and parsing an {@link XmlPullParser} into
 * a set of {@link ContentProviderOperation}. It catches recoverable network
 * exceptions and rethrows them as {@link HandlerException}. Any local
 * {@link ContentProvider} exceptions are considered unrecoverable.
 * <p>
 * This class is only designed to handle simple one-way synchronization.
 */
public abstract class XmlHandler extends BaseHandler {

	public XmlHandler(String authority) {
		super(authority);
	}

	/**
	 * Parse the given {@link XmlPullParser}, turning into a series of
	 * {@link ContentProviderOperation} that are immediately applied using the
	 * given {@link ContentResolver}.
	 */
	public void parseAndApply(XmlPullParser parser, ContentResolver resolver)
			throws HandlerException {
		try {
			final ArrayList<ContentProviderOperation> batch = parse(parser,
					resolver);
			resolver.applyBatch(mAuthority, batch);

		} catch (HandlerException e) {
			throw e;
		} catch (XmlPullParserException e) {
			throw new HandlerException("Problem parsing XML response", e);
		} catch (IOException e) {
			throw new HandlerException("Problem reading response", e);
		} catch (RemoteException e) {
			// Failed binder transactions aren't recoverable
			throw new RuntimeException("Problem applying batch operation", e);
		} catch (OperationApplicationException e) {
			// Failures like constraint violation aren't recoverable
			// TODO: write unit tests to exercise full provider
			// TODO: consider catching version checking asserts here, and then
			// wrapping around to retry parsing again.
			throw new RuntimeException("Problem applying batch operation", e);
		}
	}

	/**
	 * Parse the given {@link XmlPullParser}, returning a set of
	 * {@link ContentProviderOperation} that will bring the
	 * {@link ContentProvider} into sync with the parsed data.
	 */
	public abstract ArrayList<ContentProviderOperation> parse(
			XmlPullParser parser, ContentResolver resolver)
			throws XmlPullParserException, IOException;

}
